Detonator for land mines

ABSTRACT

A detonator for a land mine containing electric circuit means for controlling and effecting the ignition of a detonator pellet, a driving mechanism controlled by said electric circuit for delaying the ignition of said pellet for a predetermined period of time, and a movable contact device subject to a change of position away from a gravity induced initial position for closing a portion of said electric circuit means. A slidable member in the housing of said detonator when moved in one direction actuates a switch member which starts the operation of said driving mechanism and at the same time moves another movable contact member into a position between two spaced fixed contacts, both of which are connected with said electric circuit means. Upon applying an external force to said slidable member, the same is moved an additional amount and the movable contact member is brought into engagement with one of said fixed contacts, thereby closing said electric circuit means for effecting the ignition.

United States Patent [1 1 Madlener et al.

[ May 20, 1975 DETONATOR FOR LAND MINES [73] Assignee: Industrie-Werke Karlsruhe Augsburg Akt., Karlsruhe, Germany [22] Filed: June 15, 1966 [21] Appl. No.: 559,043

[56] References Cited UNITED STATES PATENTS 2/1947 Detwiler ZOO/61.52 10/1951 Ensign, Jr. 102/8 Primary Examiner-Robert F. Stahl Attorney, Agent, or Firm-McGlew and Tuttle [5 7 ABSTRACT A detonator for a land mine containing electric circuit means for controlling and effecting the ignition of a detonator pellet, a driving mechanism controlled by said electric circuit for delaying the ignition of said pellet for a predetermined period of time, and a movable contact device subject to a change of positionaway from a gravity induced initial position for closing a portion of said electric circuit means. A slidable member in the housing of said detonator when moved in one direction actuates a switch member which starts the operation of said driving mechanism and at the same time moves another movable contact member into a position between two spaced fixed contacts, both of which are connected with said electric circuit means. Upon applying an external force to said slidable member, the same is moved an additional amount and the movable contact member is brought into engagement with one of said fixed contacts, thereby closing said electric circuit means foreffecting the ignition.

7 Claims, 5 Drawing Figures mama] m 884. 1 51 SHEET 3 [1F 4 PATENTED MAY 20 I975 SHEET [1F 4 DETONATOR FOR LAND MINES The invention relates to a detonator for land mines. The detonators ordinarily used in land mines are pressure actuated detonators, which cause an explosion of the mine when something or someone travels over the release mechanism of the mine. The mines may be rendered more or less free from danger by means of unscrewing a certain part by friend and foe so that the mine is unprimed or disarmed. In order to prevent the disarming of the mines by the enemy, or at least make it difficult a series of supplemental means is known, which are placed under the mine and which upon raising of the mine body detonate. All these devices may be discovered rather rapidly by an expert as they are located outside of the actual mine body and may be rendered harmless by suitable procedures. In order to prevent an unscrewing of the detonator from the mine body, already detonator constructions have been employed, which upon unscrewing, are caused to bring the mine to detonation.

Al these constructions are not ideal solutions, as they mean additional expenditures to the actual detonator mechanism and mainly comprise supplemental devices placed outside the mine.

In order to overcome these disadvantaqes, the invention is characterized in this, that the detonator reacts to normal load, upon unauthorized unscrewing of the mine screw coupling detonates, and ignites the mine upon a change in position of the latter, in that by a depression of a pressure member with a pressure ball in direction of the axis of the detonator a driving mechanism of known construction is set in motion, and depending upon the distance of the movement an actuating bolt or a switch spring engages either a lower bracket or on an upper bracket and causes the mine to detonate by means of a primer pellet whereby at the same time a control disc is rotated about the detonator axis and operates a switch bracket by means of cams, which switch-bracket urges two oppositely disposed contact bolts into a hollow sphere connected with the detonator housing against a freely movable contact sphere lying therein and holds the latter in position, whereby the upper one carries two gilded sphericalcups separated from each other by an insulating intermediary annular member. One of said spherical cups carries a gilded conically-shaped contact plate, on which lies a gilded ball freely rolling as connection element.

Further details of the invention are described in the following description and in the claims.

This invention combines three functions of the detonator into one, which makes the ignitor economical to manufacture and furthermore, a reliable operation of the detonator is obtained.

In order on one hand, to increase the reliable manipulation of the detonator, and on the other hand, to make possible the launching of mines with such detonators, the present detonator construction is provided with a delay-drive mechanism which from the moment the drive mechanism is set in operation up to the readiness of the detonator for ignition insures a predetermined period of safety.

The invention by way of example is illustrated in the drawings by five figures.

In these drawings:

FIG. 1 is a longitudinal sectional view of the detonator.

FIG. 2 is a cross-sectional view along the line lIlI of FIG. 1.

FIG. 3 is a longitudinal sectional view of the detonator with hollow ball in section.

FIG. 4 a sectional view along the line IVIV of FIG. 3, and

FIG. 5 an electric circuit diagram of the detonator.

The detonator consists in its outer construction of a detonator housing 1, a bottom member 2, an upper screw-cap 3, a pressure actuated ball 4 and a safety bracket 5.

In the interior of the detonator housing 1 is arranged a driving mechanism 6 of customary construction, whose hollow shaft 7 extends loosely into the center bore 8 of the bottom member 2. This hollow shaft 7 is lined and fixedly connected with a control bushing 9 consisting of insulating material. The upper end of the control bushing 9 extends upwardly beyond upper end of the hollow shaft 7 in the form of a control disc 10 with control cams 11 and 11a (see FIG. 4) on its upper face.

On a plate portion 12 of the driving mechanism 6 is fixedly attached a supporting sleeve 13, on whose upper end a hollow sphere 14 extending halfway into sleeve 13 is soldered. On the lower end of the hollow sphere 14 is fixed a double-armed switch-bracket 15, which is so formed, that two offset free arms 16 (switch-bracket-ends), may be actuated by the control cams 11 on the control disc 10. Each of the free ends of the arms 16 of the switch-bracket 15 acts upon a contact bolt 17a and 17b, (FIG. 1) which are slidably mounted in an insulating member 18 and by means of a leaf spring 19 are urged outwardly against the switchbracket ends 16.

In the interior of the hollow sphere 14 is freely movably arranged a contact sphere 20 composed of two almost semi-spherical parts, which contact sphere is provided with projections 21 which engage the inner wall of the hollow sphere 14. The surface of the contact sphere 20 is gilded in form of two metal-cups 22, and between these two cups 22 lies an intermediate annular insulating member 23, which is wider than the diameter of the contact bolts 17a and 17b. In the contact sphere 20 is inserted one-sided a lead weight 24, which causes the sphere 20 to swing inside the sphere 14 in accordance with the force of gravity.

The interior of the contact sphere 20 forms a hollow chamber 25, which is divided by means of a truncated upwardly open cone of predetermined conical inclination. The cone is formed by a conical contact plate 27 made of sheet metal. It is metallically connected with the lead core 24 and with the lower cup 22 containing the lead core 24. The inner surface of the upper metal cup 22 is gilded, likewise the inner surface of the conically shaped contact plate 27 which rests with its outer edge upon the annular insulating member 23 but remains out of metallic contact with the upper cup 22.

A pressure member 30 is pushed over the hollow sphere 14 and by a helical-pressure spring 31 is urged upwardly against the screw-cap 3. On the pressure member 30 is disposed the pressure sphere 4, which is loosely held in an extension of the screw-cap 3.

The safety bracket 5 engages with its two ends two oppositely arranged bores in the screw-cap 3 and resiliently engages from below the center of the pressure sphere 4 and prevents an unintentional actuation of the detonator. Upon removal of the safety-bracket 5, the pressure sphere 4 is moved a predetermined distance downwardly, and an extended sleeve 32 of the pressure member 30 presses upon a vertically arranged resilient switch-bolt 33 (FIG. 1), which releases the driving mechanism 6.

At the same time, the extended sleeve 32 of the pressure member 30 reaches an actuating bolt 34 (FIG. 3), which is pressed downwardly upon a switch spring 35 and moves the latter into a position in the center between the switch brackets (see also FIG. Means are provided to retain the sleeve 32 and the switch spring 35 in this position. If now an additional pressure is exerted upon the pressure sphere 4, the pressure member is moved farther downward so that the switch spring engages the lower switch bracket 36 and the result is, as will be explained hereinafter, that the ignition circuit is closed when the same is in an armed condition. A closing of the ignition circuit, when the mine is armed, also takes place when the pressure member 30 owing to the upwardly directed inner tension of the switch spring 35 is moved upwardly so that the switch spring 35 engages the upper switch bracket 37.

In the portion of the control bushing 9 projecting from the upper end of the hollow axis 7 is seated loosely in a depression 38 a gilded steel ball or sphere 39 (FIG. 2); the latter is supported on a contact plate 40, which is soldered to a conductor wire 41. During the run-off of the driving mechanism 6, the sphere or ball 39 rolls along a stationary insulating guide-way 42, until it touches or rolls up against a contact disc 43 and stops the operation of the driving mechanism 6 for example after five minutes. The contact disc 43 is soldered to a conductor wire 44, which leads to the contact 17b. The detonator is now alive.

In the interior of the control bushing 9 is preferably arranged a gastight miniature battery in the form of a rod element 45 as source of energy for the release of the detonator. The one pole of the rod element is supported on a contact spring 46, which is connected with the contact pin 17a and is conductively connected with the central switching spring 35 (FIG. 5). The other pole engages a contact 47 which is conductively connected with the one conducting wire of an electric detonator pellet 48. The detonator pellet 48 is inserted in a threaded detonator plug 49 of insulating material. The second conductor wire of the detonator pellet 48 by means of a conducting expansion spring 50 and a contact ring 51 inserted in the control bushing 9 is conductively connected with the conductor wire 41, contact plate 40 and the sphere 39. The conductor wire leaving the contact disc 43 is connected with the contact pin 17b and simultaneously with the switchspring 36 and 37. After the run-off of the driving mechanism, a conducting connection is produced by a rotation of the axis of the driving mechanism between the contact plate 40 and the contact disc 43 and the sphere 39.

The operation is as follows:

As the detonator is screwed into the mine and, after removal of the safety bracket 5, the mine is screwed closed, the pressure ball or sphere 4 is being pressed downward a determined amount. Thereby, the extended slidable sleeve 32, urges the switch bolt 33 downwardly, which releases the driving mechanism 6, which begins to operate. After a predetermined rotative movement limited by means of the radially directed contact disc 43, the steel ball 39 closes a part of the electric circuit.

Simultaneously the control disc 10 has rotated, and has actuated by the earns 11 the switch brackets 15, which press the contact bolts 17a and 17b into the hollow sphere 14, where they are seated on the cups 22 of the previously freely movable ball or sphere 20, which on account of the one-sided lead weight 24 has adjusted itself according to the force of gravity. The contact bolts 17a and 17b hold the ball 20 in this position. The two parts insulated from one another, contact-cone 27 and upper contact-semi-sphere 22, now are connected with the battery 45.

If now a change in position of the deposited mines takes place, the ball 26 rolls outward and connects the two parts namely the contact-cone 27 and upper semispherical contact member 22 with one another. Thereby a circuit-closure is produced through the electric detonator pellet 48 and it is ignited. The sensitivity against a change of position may be attained by means of a corresponding inclination of the conically shaped contact plate 27. If due to ground shocks as a result of detonations occurring in the vicinity, in the mines at rest the contact ball 26 should jump up, it is thrown into the hollow chamber 25 and, without having any effect, drops back into the conical tip of the contact plate 27.

If a load moves over the mine, the pressure ball 4 is pressed a predetermined amount farther into the detonator. The extended slidable sleeve 32 shifts the actuating bolt 34 downward, which presses the contact spring 35 against the switch bracket 36. Thereby the circuit is again closed through the detonator pellet 48 and the mine detonated.

If the enemy attempts to disarm the mine, in that he unscrews the mine in order to remove the detonator, the pressure spring 31 shifts the alidable member 32 upwardly. The actuating bolt 34 is relieved of its load and permits the contact spring 35 to engage the switch bracket 37. Again the circuit through the detonator pellet 48 is closed and the mine detonated.

What we claim is:

1. In a detonator for a land mine, a detonator housing having mounted therein an electrically ignitable detonator pellet, electric circuit means for controlling the ignition of said pellet, a drive mechanism controlled by a switch member (33) in said circuit means for delaying the ignition of said pellet for a predetermined period of time, a movable contact device subject to a change of position of said housing with respect to an initial position for closing a portion of said electric circuit means when a change of the position of said housing from its initial position takes place, gravity controlled means for moving said movable contact device into said initial position in which said portion of said circuit means is open, a slidable member (32) in said housing, said electrical circuit means also including two spaced fixed contact members (36, 37) and a movable contact member (35) therebetween, said slidable member when moved in one direction actuating said switch member (33) to start the operation of said driving mechanism and at the same time moving said movable contact member (35) into a position midway between and out of engagement with said two spaced fixed contact members.

2. A detonator according to claim 1, including means for slidably moving said slidable member (32) in one direction by a pressure transmitted to it by an external force, whereby said movable contact member (35) is brought into engagement with one of said spaced fixed contact members (36, 37) to effect a closing of said electric circuit, said movable contact member upon cessation of said external force being adapted to move in the opposte direction into engagement with said other fixed contact member.

3. A detonator according to claim 1, in which said slidable member comprises a sleeve movable in the axial direction of said housing, said sleeve surrounding said movable contact device, and a slidably mounted actuating bolt (34) between one end of said sleeve and said movable contact member (35) for engaging the latter when said sleeve is axially moved by an external force, so that said movable contact member is moved in engagement with one of said two spaced fixed contact members.

4. A detonator according to claim 1, including a bottom wall at one end of said housing, said driving mechanism being attached to said bottom wall and including a tubular shaft (7) extending through a central aperture in said bottom wall, a control bushing (9) of insulating material extending through said tubular shaft and provided at one end which extends beyond the end of said tubular shaft into the interior of said housing with a recess (38), a steel ball (39) within said recess and in electrical connection with said electric circuit, a stationary guideway extending concentrically about said bushing and along which said ball is adapted to roll when said driving mechanism is operating, a contact disc at the end of said guideway for stopping said ball and the operation of said driving mechanism, and means conductively connecting said contact disc with said electric circuit to arm said detonator.

5. Detonator according to claim 1, in which said movable contact device includes a freely rotatably mounted hollow ball comprising two semispherical metal cups (21, 22) and an intermediate annular insulating member (23) uniting said cups, means for connecting each of said cups to said electric circuit,

a metallic conical plate (27) with its circumference facing upwardly being mounted on said insulating member, means for conductively connecting said conical plate with the cup below said annular insulating member, said last named cup containing a lead weight tending to rotate said contact device by gravity into said initial position, a contact ball (26) loosely positioned in the cavity formed by said conical plate and adapted to make electrical contact with the upper cap when said hollow ball is caused to rotate about its center, thereby connecting both said semi-spherical cups by means of said conical plate in series in said electric circuit.

6. Detonator according to claim 5, including a fixedly mounted hollow spherical casing (14) in which said hollow ball (20) is freely rotatably mounted, two yieldably mounted contact members (17a 17b) arranged on said casing and adapted to be brought into engagement with said two semi-spherical cups respectively, said two contact members forming part of said means for connecting each of said cups with said electric circuit, and means operated by said driving mechanism for urging said two yieldably mounted contact members into engagement with their respective semi-spherical cups so as to arrest the hollow ball (20) in the prevailing posi tion.

7. Detonator according to claim 5, including a fixedly mounted hollow spherical casing (14) in which said hollow ball (20) is freely rotatably mounted, two yieldably mounted contact members (17a, 17b) arranged on said casing and adapted to be brought into engagement with said two semi-spherical cups respectively, said two contact members forming part of said means for connecting each of said cups with said electric circuit, and means operated by said driving mechanism for urging said two yieldably mounted contact members into engagement with their respective semi-spherical cups so as to arrest the hollow ball (20) in the prevailing position, said last named means including a cam-carrying control disc (10) rotated by said driving mechanism and a switch bracket (15) actuated by the same, said switch bracket having means thereon for engaging said yieldably mounted contact members. 

1. In a detonator for a land mine, a detonator housing having mounted therein an electrically ignitable detonator pellet, electric circuit means for controlling the ignition of said pellet, a drive mechanism controlled by a switch member (33) in said circuit means for delaying the ignition of said pellet for a predetermined period of time, a movable contact device subject to a change of position of said housing with respect to an initial position for closing a portion of said electric circuit means when a change of the position of said housing from its initial position takes place, gravity controlled means for moving said movable contact device into said initial position in which said portion of said circuit means is open, a slidable member (32) in said housing, said electrical circuit means also including two spaced fixed contact members (36, 37) and a movable contact member (35) therebetween, said slidable member when moved in one direction actuating said switch member (33) to start the operation of said driving mechanism and at the same time moving said movable contact member (35) into a position midway between and out of engagement with said two spaced fixed contact members.
 2. A detonator according to claim 1, including means for slidably moving said slidable member (32) in one direction by a pressure transmitted to it by an external force, whereby said movable contact member (35) is brought into engagement with one of said spaced fixed contact members (36, 37) to effect a closing of said electric circuit, said movable contact member upon cessation of said external force being adapted to move in the opposte direction into engagement with said other fixed contact member.
 3. A detonator according to claim 1, in which said slidable member comprises a sleeve movable in the axial direction of said housing, said sleeve surrounding said movable contact device, and a slidably mounted actuating bolt (34) between one end of said sleeve and said movable contact member (35) for engaging the latter when said sleeve is axially moved by an external force, so that said movable contact member is moved in engagement with one of said two spaced fixed contact members.
 4. A detonator according to claim 1, including a bottom wall at one end of sAid housing, said driving mechanism being attached to said bottom wall and including a tubular shaft (7) extending through a central aperture in said bottom wall, a control bushing (9) of insulating material extending through said tubular shaft and provided at one end which extends beyond the end of said tubular shaft into the interior of said housing with a recess (38), a steel ball (39) within said recess and in electrical connection with said electric circuit, a stationary guideway extending concentrically about said bushing and along which said ball is adapted to roll when said driving mechanism is operating, a contact disc at the end of said guideway for stopping said ball and the operation of said driving mechanism, and means conductively connecting said contact disc with said electric circuit to arm said detonator.
 5. Detonator according to claim 1, in which said movable contact device includes a freely rotatably mounted hollow ball (20) comprising two semi-spherical metal cups (21, 22) and an intermediate annular insulating member (23) uniting said cups, means for connecting each of said cups to said electric circuit, a metallic conical plate (27) with its circumference facing upwardly being mounted on said insulating member, means for conductively connecting said conical plate with the cup below said annular insulating member, said last named cup containing a lead weight tending to rotate said contact device by gravity into said initial position, a contact ball (26) loosely positioned in the cavity formed by said conical plate and adapted to make electrical contact with the upper cap when said hollow ball is caused to rotate about its center, thereby connecting both said semi-spherical cups by means of said conical plate in series in said electric circuit.
 6. Detonator according to claim 5, including a fixedly mounted hollow spherical casing (14) in which said hollow ball (20) is freely rotatably mounted, two yieldably mounted contact members (17a 17b) arranged on said casing and adapted to be brought into engagement with said two semi-spherical cups respectively, said two contact members forming part of said means for connecting each of said cups with said electric circuit, and means operated by said driving mechanism for urging said two yieldably mounted contact members into engagement with their respective semi-spherical cups so as to arrest the hollow ball (20) in the prevailing position.
 7. Detonator according to claim 5, including a fixedly mounted hollow spherical casing (14) in which said hollow ball (20) is freely rotatably mounted, two yieldably mounted contact members (17a, 17b) arranged on said casing and adapted to be brought into engagement with said two semi-spherical cups respectively, said two contact members forming part of said means for connecting each of said cups with said electric circuit, and means operated by said driving mechanism for urging said two yieldably mounted contact members into engagement with their respective semi-spherical cups so as to arrest the hollow ball (20) in the prevailing position, said last named means including a cam-carrying control disc (10) rotated by said driving mechanism and a switch bracket (15) actuated by the same, said switch bracket having means thereon for engaging said yieldably mounted contact members. 